Rendering Algorithms

• The rapid motion rendering method (also knowns as scanline rapid) has bee replaced with a new renderer called rasterizer, which is an alternative to the regular scanline renderer. A key benefit of this algorithm is that it separates shading samples from visibility samples. It can therefore be more efficient for scense which do not requrire ray tracing, with or without motion blur.

  For backwards compatibility, the existing controlling options were mostly retained. The rasterizer is enabled with the scanline rapid option. The approximation, and hence the sampling rate and antialiasing of shading, is controlled by the new option shading samples in the .mi syntax. The number of pixel samples is as before controlled by the samples collect option.

• Several improvements of the speed and image quality of final gathering have been made. Note that it may be necessary to alter final gathering parameters in order to achive comparable render times (at mostly increased image quality).
• In order to be able to render larger amounts of hair without running out of memory, large hair objects are now internally split up into smaller portions when using the rasterizer or when creating shadow maps.
• Frame buffers are now stored on disk during rendering in order to be able to use arbitrarily many and arbitrarily large frame buffers. This is implemented using memory mapping. This new feature can be disabled using the option -fb_virtual off.
• In the hardware rendering mode, motion blur has been implemented, intended for rough pre-visualization of motion.
• When computing light maps in combination with network rendering, light maps are now no longer computed on rendering slave hosts, but only on the master host.
• mental ray now support version 1.2.1 of the OpenEXR image file format. Mipmapping, texture tiling, and texture caching are now supported for OpenEXR textures, and multiple image types (i.e. frame buffers) can now be written to a single OpenEXR output image file.

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